/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.camera;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.View;

import com.example.dellpc.myapplication.R;
import com.google.zxing.ResultPoint;

import java.util.Collection;
import java.util.HashSet;

/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial
 * transparency outside it, as well as the laser scanner animation and result points.
 * �Զ����View������ʱ�м���ʾ��
 */
public final class ViewfinderView extends View {

  private static final int[] SCANNER_ALPHA = {0, 64, 128, 192, 255, 192, 128, 64};
  private static final long ANIMATION_DELAY = 100L;
  private static final int OPAQUE = 0xFF;

  private final Paint paint;
  private Bitmap resultBitmap;
  private final int maskColor;
  private final int resultColor;
  private final int frameColor;
  private final int laserColor;
  private final int resultPointColor;
  private int scannerAlpha;
  private Collection<ResultPoint> possibleResultPoints;
  private Collection<ResultPoint> lastPossibleResultPoints;
  /**
   * 手机的屏幕密度
   */
  private static float density;
  /**
   * 四个绿色边角对应的长度
   */
  private int ScreenRate;
  /**
   * 中间滑动线的最顶端位置
   */
  private int slideTop;
  private boolean isFirst;
  // This constructor is used when the class is built from an XML resource.
  public ViewfinderView(Context context, AttributeSet attrs) {
    super(context, attrs);

    // Initialize these once for performance rather than calling them every time in onDraw().
    paint = new Paint();
    Resources resources = getResources();
    maskColor = resources.getColor(R.color.viewfinder_mask);
    resultColor = resources.getColor(R.color.result_view);
    frameColor = resources.getColor(R.color.white);
    laserColor = resources.getColor(R.color.viewfinder_laser);
    resultPointColor = resources.getColor(R.color.possible_result_points);
    scannerAlpha = 0;
    possibleResultPoints = new HashSet<ResultPoint>(5);
    density = context.getResources().getDisplayMetrics().density;
    // 将像素转换成dp
    ScreenRate = (int) (20 * density);
  }

  @Override
  public void onDraw(Canvas canvas) {
    Rect frame = CameraManager.get().getFramingRect();
    if (frame == null) {
      return;
    }
    int width = canvas.getWidth();
    int height = canvas.getHeight();
    // 初始化中间线滑动的最上边和最下边
    if (!isFirst) {
      isFirst = true;
      slideTop = frame.top - 5;
    }
    //预览界面的绘制 Draw the exterior (i.e. outside the framing rect) darkened
    paint.setColor(resultBitmap != null ? resultColor : maskColor);
    canvas.drawRect(0, 0, width, frame.top, paint);
    canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
    canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
    canvas.drawRect(0, frame.bottom + 1, width, height, paint);

    if (resultBitmap != null) {
      // Draw the opaque result bitmap over the scanning rectangle
      paint.setAlpha(OPAQUE);
      canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
    } else {

      // 画扫预览线框，共4个部分Draw a two pixel solid black border inside the framing rect
      paint.setColor(frameColor);
      canvas.drawRect(frame.left, frame.top, frame.right + 1, frame.top + 2, paint);
      canvas.drawRect(frame.left, frame.top + 2, frame.left + 2, frame.bottom - 1, paint);
      canvas.drawRect(frame.right - 1, frame.top, frame.right + 1, frame.bottom - 1, paint);
      canvas.drawRect(frame.left, frame.bottom - 1, frame.right + 1, frame.bottom + 1, paint);
      //画出四个角总共8个部分
      paint.setColor(getResources().getColor(R.color.text_pink));
        canvas.drawRect(frame.left, frame.top, frame.left + 20,
                frame.top + 6, paint);
        canvas.drawRect(frame.left, frame.top, frame.left + 6,
                frame.top + 20, paint);
        canvas.drawRect(frame.right - 20, frame.top, frame.right,
                frame.top + 6, paint);
        canvas.drawRect(frame.right - 6, frame.top, frame.right,
                frame.top + 20, paint);
        canvas.drawRect(frame.left, frame.bottom - 6, frame.left
                + 20, frame.bottom, paint);
        canvas.drawRect(frame.left, frame.bottom - 20, frame.left
                + 6, frame.bottom, paint);
        canvas.drawRect(frame.right - 20, frame.bottom
                - 6, frame.right, frame.bottom, paint);
        canvas.drawRect(frame.right - 6, frame.bottom
                - 20, frame.right, frame.bottom, paint);

      // Draw a red "laser scanner" line through the middle to show decoding is active
      // 绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE
      slideTop += 10;
      if (slideTop >= frame.bottom - 10) {
        slideTop = frame.top - 5;
      }
      Rect lineRect = new Rect();
      lineRect.left = frame.left;
      lineRect.right = frame.right;
      lineRect.top = slideTop;
      lineRect.bottom = slideTop + 30;// 扫描线的宽度15
      canvas.drawBitmap(((BitmapDrawable) (getResources().getDrawable(R.mipmap.qrcode_scan_line))).getBitmap(),
              null, lineRect, paint);
      paint.setColor(Color.WHITE);
      paint.setTextSize(15 * density);
      paint.setAlpha(0xee);
      paint.setTypeface(Typeface.create("System", Typeface.BOLD));

      Collection<ResultPoint> currentPossible = possibleResultPoints;
      Collection<ResultPoint> currentLast = lastPossibleResultPoints;
      if (currentPossible.isEmpty()) {
        lastPossibleResultPoints = null;
      } else {
        possibleResultPoints = new HashSet<ResultPoint>(5);
        lastPossibleResultPoints = currentPossible;
        paint.setAlpha(OPAQUE);
        paint.setColor(resultPointColor);
        for (ResultPoint point : currentPossible) {
          canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 6.0f, paint);
        }
      }
      if (currentLast != null) {
        paint.setAlpha(OPAQUE / 2);
        paint.setColor(resultPointColor);
        for (ResultPoint point : currentLast) {
          canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 3.0f, paint);
        }
      }

      // Request another update at the animation interval, but only repaint the laser line,
      // not the entire viewfinder mask.
      postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom);
    }
  }

  public void drawViewfinder() {
    resultBitmap = null;
    invalidate();
  }

  /**
   * Draw a bitmap with the result points highlighted instead of the live scanning display.
   *
   * @param barcode An image of the decoded barcode.
   */
  public void drawResultBitmap(Bitmap barcode) {
    resultBitmap = barcode;
    invalidate();
  }

  public void addPossibleResultPoint(ResultPoint point) {
    possibleResultPoints.add(point);
  }

}
